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Subject: 
Re: Planes & Requirements for a generic download-tool
Newsgroups: 
lugnet.cad.dev
Date: 
Thu, 13 Jul 2000 10:34:15 GMT
Reply-To: 
[rui.martins@link]NoSpam[.pt]
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On Thu, 13 Jul 2000, Michael Lachmann wrote:

Hy,

after exchanging some mails with Tim Courtney, I'm planing to write a generic
download-utility for LDraw/LEdit stuff.

Great to see someone is in sink with me !
I have been planning this for a while too !

The basic idea behind is to have a utility which can be used to download a
specific program and/or the part libraries. Also an automatic upgrade process
shell be possible like it's known from many anti virus tools.
In general the tool should take care about everything what is necessary to get
a certain program running and to keep it and the libraries up-to-date.

I was thinking more on the line of an update for the Oficial DATs, but this can
be easilly extended if a config file for each program/library can be defined.

I saw that it is possible to extract the executables Ledit.exe and
Complete.exe using WinZip and I will check if it is also possible using GZip.
If yes I will include gnu-zip code into the program to automatically unpack
the packages.

Question to Tim: Would it be possible for you to activate an ftp server at
ldraw.org where you put everything in which is download-able? This would make
the whole thing more easy to program (at least for me ...).

I have researched the FTP protocol in some depth, and it is the best and
simplest solution.
The only problem is how to extract the file info (size, date/time stamp, etc) to
be able to determine which files need update.
Currently there are two solutions (at least the ones I see), we need to
supported the two different listing outputs from FTP servers (Windows and Unix),
and extract the info from the listings (parse it)
or
we could build an index file (which is kept updated on the server), which has
this info for each file.

Both solution have Pros and Cons:
The first, since it's in the windows environment, if you just view the file,
it's time stamp it will be changed, even if no change is done. I'm Not sure why
this happens, or even why sometimes it doesn't, strange!
We wouldn't need to keep an index file nor in the server, nor in every user
client computer.

The second implies that we will be vulnerable to human error, Not updating the
file, or erroneously updating it.
We must keep the index file in the server and in the user client computer.

Another thing is that I would like to ask to include a certain text-file into
the complete.exe and updates which cleary states the which update is included
in the package so tracking would be easy.

Well the ideia to use the FTP protocol implies that in the download server
(ftp://www.ldraw.org), the DAT files have to be decompressed, or else there is
no bandwith savings when updating, it would be better to download the
"complete.exe" all over again, by hand.

The ideia is:
if only 5 files have changed, the user only needs to download these 5 files.
and by change I meen relative to the user setup. if someone hasn't updated for a
long time, then they will have a lot to download to get in sync.

I also had thought already that a listing of the "need update" files would be
supplied to the user, and he would be allowed to choose which of the files, or
eventually all required to sync (the default).
So not to force people with less bandwith to get it all at once, they can resync
later.

Also if the FTP server was running Unix, we could make the ftp server compress
the files on the fly, if the user (Loader program) request for example
"stud.dat" has "stud.dat.gz" or "stud.dat.zip"

Please tell me if somebody would like to help me in writing this stuff and
maybe you have other ideas based on this proposal.

I started a project which I haven't completed iet, and currently I honestly
don't know where it is, since I changed home a few months ago.
But if I can't find it I can start from scratch, I hadn't done much work on it !
But I planned to release this could so that it could be maintainable by the
comunity.

Well about the ideias I think I have informed you about all I can remember right
Now !

See ya

Rui Martins



Message is in Reply To:
  Planes & Requirements for a generic download-tool
 
Hy, after exchanging some mails with Tim Courtney, I'm planing to write a generic download-utility for LDraw/LEdit stuff. The basic idea behind is to have a utility which can be used to download a specific program and/or the part libraries. Also an (...) (24 years ago, 13-Jul-00, to lugnet.cad.dev)

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